In vivo supporting devices or barrier devices, such as stents, is a man-made “tube” or “frame” inserted into a natural passage or conduit in the body to prevent, or counteract, a disease-induced, localized flow constriction or flow outflow like a leak or aneurysm. Supporting devices include vascular supporting devices, non-vascular supporting devices, and heart failure closure or aneurysm sealing devices. Vascular supporting devices are designed for applications in the vascular system, such as arteries and veins. Non-vascular supporting devices are used in other body lumens such as biliary, colorectal, esophageal, uretheral and urethral tract, and upper airway. Heart failure closure devices are used to correct defects in heart, such as atrial septal defect (ASD), patent foramen ovale (PFO) and ventricular septal defect (VSD). Aneurysm sealing devices are used to close off potentially dangerous aneurysm or pseudo aneurysm throughout the vascular and non-vascular system.
In vivo supporting devices are typically made from a rigid material, such as a metal, alloy or rigid polymeric material. The supporting device may be made from a biodegradable material so that there is no need to remove the device after the correction of the underline defects. A common problem with the biodegradable supporting device, however, is that the device may disintegrate in an uncontrolled manner and break into large pieces which, if entering the circulation of a body fluid such as blood, may interfere with the normal circulation of the body fluid. Therefore, there exists a need for improved in vivo supporting devices that are biodegradable in a controlled manner.